1. Description of the Art
Over the past few years, the demand for ever cheaper and lighter weight portable electronic devices has led to a growing need to manufacture durable, lightweight, and low cost electronic circuits of increasing complexity, including high density memory chips. To a large extent, over the past thirty years, this growth has been fueled by a nearly constant exponential increase in the capabilities of microelectronic devices; producing unprecedented advances in computational, telecommunication, and signal processing capabilities. In turn, this increase in complexity has driven a corresponding decrease in the feature size of integrated circuit devices, which has typically followed xe2x80x9cMoore""s Law.xe2x80x9d However, the continued decrease in feature size of integrated circuits, into the nanometer regime, has become increasingly more difficult, and may be approaching a limit, because of a combination of physical and economic reasons.
Prior proposed solutions to the problem of constructing nanometer-scale devices have typically fallen into two broad categories, one general area can be described as new patterning techniques, the other general area involves new materials having nanometer-scale dimensions. New patterning techniques include both projection systems utilizing radiation, and direct write systems utilizing particle beams, or scanning probes. Some of the newer higher resolution projection systems require expensive radiation sources such as synchrotrons. On the other hand direct write systems, typically, require a serial process of individually writing each structure in contrast to exposing many structures at one time utilizing projection systems. Thus, direct write systems, typically, have a much lower throughput when compared to projection systems again leading to either increased complexity in manufacturing or increased cost or both.
Recently new materials having semiconducting properties and nanometer-scale dimensions have been synthesized and fabricated into nanometer-scale devices. However, after these nanometer-scale materials are formed, they are often randomly arranged, either one end randomly attached to a substrate or both ends free. This randomness along with the difficulty of physically manipulating nanometer-sized components presents a significant challenge to the fabrication of reproducible and practical nanometer-scale devices.
If these problems persist, the continued growth, seen over the past several decades, in cheaper, higher speed, higher density, and lower power integrated circuits used in electronic devices will be impractical.